Photoresist dispense method by compensation for substrate reflectivity

Abstract

In the manufacture of a semiconductor device, a method for forming a layer on a semiconductor substrate compensates for variations in wafer substrate reflectivity. The method includes providing substrate illumination and then adjusting the illumination on the substrate. The method also includes controlling the dispensation of material over the substrate as a function of the adjusted illumination. By compensating for variations in wafer substrate reflectivity, manufacturing processes can realize more consistent photoresist coatings on wafer substrates from one wafer lot to another.

What is claimed is:  
     
       1. In the manufacture of a semiconductor device, a method for forming a layer over a semiconductor substrate, comprising: 
       providing illumination on the substrate;  
       adjusting the illumination; and  
       controlling the dispensation of a material over the substrate as a function of the adjusted illumination.  
     
     
       2. The method according to claim  1 , wherein adjusting the illumination includes detecting the illumination, and measuring light that is reflected from the substrate. 
     
     
       3. The method according to claim  1 , further including adjusting the illumination of the substrate to an optimum level of substrate reflectivity. 
     
     
       4. The method according to claim  3 , wherein controlling dispensation of material includes: 
       dispensing the material after the substrate reflectivity has been optimized; and  
       detecting when the dispensed material contacts the substrate.  
     
     
       5. The method according to claim  1  wherein adjusting the illumination includes: 
       detecting a level of substrate reflectivity; and  
       optimizing the level of substrate reflectivity by adjusting the intensity of substrate illumination.  
     
     
       6. The method according to claim  2 , wherein detecting the illumination includes using a photodiode detector. 
     
     
       7. The method according to claim  6 , wherein controlling the dispensation includes coupling a light source to the photodiode detector. 
     
     
       8. The method according to claim  2 , wherein controlling the dispensation includes defining a light-controlled environment and optimizing the illumination on the substrate to a given level of substrate reflectivity. 
     
     
       9. The method according to claim  8 , wherein the light-controlled environment includes providing an enclosure for forming therein the layer over the substrate, the enclosure including walls having a non-reflective material coating thereon. 
     
     
       10. The method according to claim  1 , further including adjusting the illumination after forming a first layer on the substrate prior to forming a second layer over the semiconductor substrate. 
     
     
       11. A method for forming a layer over a semiconductor substrate, comprising: 
       providing illumination on the substrate;  
       detecting a level of substrate reflectivity;  
       optimizing the level of substrate reflectivity by adjusting the intensity of substrate illumination;  
       dispensing a material over the substrate after the substrate reflectivity has been optimized; and  
       detecting when the dispensed material makes contact with the substrate.  
     
     
       12. The method according to claim  11 , wherein detecting the substrate reflectivity includes using a photodiode detector. 
     
     
       13. The method according to claim  11 , further including providing an enclosure for forming therein the photoresist layer on the substrate, the enclosure including walls having a non-reflective material coating thereon, whereby signal noise is reduced and substrate reflectivity measurement is improved. 
     
     
       14. The method according to claim  13 , wherein one of the walls has a reduced transparent window area for viewing the photoresist layer deposition. 
     
     
       15. The method according to claim  1 , wherein the step of controlling the dispensation of a material includes controlling the dispensation of a photoresist material. 
     
     
       16. The method according to claim  1 , wherein the step of adjusting the illumination includes providing a light source controller coupled to a light detector. 
     
     
       17. The method according to claim  4 , further including the step of providing an imaging device for detecting when the dispensed material contacts the substrate.